Fresenburg, an estate in Holstein near Oldesloe between Hamburg and Lübeck, Germany, which was in the possession of the van Ahlefeldt family in 1526-1641. Bartholomäus van Ahlefeldt, who had learned to know the persecuted Anabaptists, granted them refuge on his Fresenburg estate from 1543 on. In 1554 an Anabaptist printer from Lübeck was examined in Oldesloe where he had planned to continue his trade. From here he proceeded to the Fresenburg estate where van Ahlefeldt had a house built for him to be used as print shop. It is likely that it was at this time that Menno Simons left Wismar and proceeded to Fresenburg, which increasingly became a refuge for Anabaptists. Although King Christian III of Denmark did his utmost to have van Ahlefeldt remove the Anabaptist refugees from his estate, he remained their protector. Here the books of Menno Simons were printed from that time on.

In the days of Menno Simons and after there was very likely a large settlement and congregation here. Gerrit Roosen, whose grandmother knew Menno Simons, reports about conditions at that time. Anabaptists from surrounding communities such as Oldesloe came here to worship. Although mandates against the Anabaptists were issued by King Christian III in 1555 and by his brother in 1557, the group was protected by their benefactor. There is a story that Menno Simons' printer was taken prisoner and was freed by van Ahlefeldt by force. During the Thirty Years' War the settlement was destroyed and many of the Mennonites moved to Altona and Glückstadt. In 1656 King Frederick III and also Duke Frederick III (each of whom ruled a part of the district) issued a mandate against the few remaining families, who were finally granted permission to stay. This was the last mention of Mennonites in the Fresenburg area.

In 1902 a monument was erected by the German Mennonites on the place where, according to popular tradition, Menno Simons was buried in 1561 on the Menno-berg. A bronze plate shows Menno holding the Bible in his hands. Not far from this site, the house in which Menno Simons' writings supposedly were printed and the linden tree which he is supposed to have planted in front of it still stand. After World War II the monument was moved near the linden tree and house.